The invention relates to fuel dispensing nozzles, including those of the type described in my U.S. Pat. Nos. 4,056,131, 4,057,086 and 4,343,337, and in my pending U.S. application Ser. Nos. 07/706,807, filed May 29, 1991, and Ser. No. 07/816,748, filed Jan. 2, 1992, the disclosures of which are incorporated herein by reference, and in particular to those fuel dispensing nozzles having the feature of vapor recovery, and to vapor flow control assemblies for use with such nozzles.
It is known to provide separate diaphragm assemblies for vapor regulation and high/low pressure sensing shutoff features. For example, Healy U.S. Pat. No. 4,056,131 describes a vapor handling arrangement in which a vapor regulator valve closes when excess vacuum is applied. A simple diaphragm has one side exposed to the atmosphere and the other side exposed to a vapor conduit. Excess vacuum in the conduit draws the diaphragm onto its seat to close the valve. A second diaphragm disposed above the first is exposed to the Venturi effect of the fuel being dispensed. The second diaphragm shuts down the vacuum by constraining the first diaphragm when fuel is not being dispensed.
Healy U.S. Pat. No. 4,057,086 describes a vapor handling nozzle with a diaphragm. When the end of the nozzle spout becomes immersed in fuel, e.g. indicating that the vehicle fuel tank is full, vacuum generated by the Venturi effect of fuel delivered through a constrained passageway in the nozzle causes the diaphragm and an associated plunger to move upward to interrupt fuel delivery. Also, when vapor pressure in the fuel tank exceeds a predetermined level, the diaphragm and plunger are caused to move downward to interrupt fuel delivery.
Healy U.S. Pat. No. 4,343,337 describes a fuel dispensing nozzle with a pair of diaphragms that operate to interrupt flow when conditions of over-pressure or under-pressure exist.
It is also known to provide a fuel dispensing nozzle that shuts off automatically when the tip of the spout is raised above its horizontal axis. One approach for achieve this objective is to provide an elongated chamber in the body of the nozzle, parallel with the horizontal axis of the nozzle. A ball is disposed inside the chamber and rolls backwards to actuate an automatic shutoff mechanism when the nozzle is raised above its horizontal axis.